Field Treatment & Prevention of Contracting Skin Infections

Wednesday, February 20, 2013

Ann Fang, EMT-B

Cynthia Goss, BA, MICP

Dave Williams, MICP

James F. Goss, MHA, MICP

Joslyn De Los Santos, EMT-B

Randy Yergenson, MICP

You’ve been working in prehospital emergency medical care for years. Your response area is a crowded urban city. You wear gloves on every call, but you never disinfect the ambulance before you start your shift and you spend a lot of time at the hospital because of long bed delays. You have noticed a few itchy raised red lesions resembling spider bites on the back of your wrists during the past few weeks. You suspect you’re being bitten by insects and pay no attention.

From 1997 to 2005, medical offices and emergency department visits for skin infections nearly doubled, from 8.6 to 14.2 million.(1) They are common among all populations and are the most common reasons for hospital admissions of IV drug users.(2) The majority of skin infections are caused by Staphylococcus aureus (S. aureus) or Streptococcus. However, EMS providers should be aware of the other important infections and infestations that affect the skin.

Infections are classified according to their anatomical distribution and subsequent signs and symptoms. Physical examination alone isn’t sufficient to diagnose skin infections, which is why computer tomography (CT) and magnetic resonance imaging (MRI) are proving to be helpful tools in diagnosing the type and extent of skin infections.(2)

Staphylococcus AureusS. aureus can lead to skin infections ranging from minor to severe. For example, folliculitis is, at less than five millimeters, a tiny and minor infection of the hair follicle. The infected site will appear red and contain pus. Treatment involves simple application of a warm compress and topical or, rarely, oral antibiotics.(2)

Furunculosis is deeper than folliculitis, involving dermal tissue. Its appearance resembles that of a nodule or boil. Furunculosis occurs most commonly on the face, neck, buttocks and axillae of people with a lot of body hair. Treatment involves incision and drainage of the infected site, or local wound care if the site is draining spontaneously. Antibiotics are administered if the patient presents with systemic symptoms.(2)

A carbuncle is a group of furuncles that occur contiguously, appearing as one large mass. The carbuncle appears inflamed and may have pus drainage from multiple follicles. The most common location is the nape of the neck, with infection frequently extending laterally. The patient may experience fever, fatigue or other systemic symptoms. Carbuncles require warm, moist compresses, antibiotic therapy and surgical drainage.(2)

Subcutaneous abscesses are groupings of purulent materials. These abscesses are often spherical, warm to the touch and tender. They have a distinct border containing white or yellow pus. Infection often occurs secondary to minor trauma, with risk increasing for bite wounds or when apocrine or sebaceous glands are obstructed. IV drug users are at greatly increased risk for abscesses, especially deep abscesses. Though the patient may have no systemic symptoms, genital abscesses (especially on men) require transport for evaluation to rule out Fournier’s gangrene.(2)

A particular type of subcutaneous abscess worth noting is the extensive perirectal abscess. The patient will often complain of an abscess on the buttocks that extends to the perineum or to the ischiorectal space. They may feel pain while sitting or defecating, and they will have a fever and appear sick. Perirectal abscesses have, at 6%, a higher mortality rate than other abscesses, and these patients should be transported for evaluation.(2)

Treatment of subcutaneous abscesses involves incision and drainage of the abscess in the emergency department. Suspected necrotizing infection or abscesses to sensitive areas, such as the face or hands, are treated in the operating room setting. Antibiotic treatment is administered, as well as endocarditis prophylaxis in patients with underlying cardiac problems. Prehospital treatment involves lightly covering the area with sterile gauze and treating systemic symptoms as needed.(2)

Methicillin-Resistant Staphylococcus Aureus (MRSA)
MRSA is the chief bacterial infection among hospitalized patients, affecting 49.1%, and the second most common bacterial infection among the outpatient population, at 41.4%.(3)

MRSA is a methicillin-resistant strain of the bacteria S. aureus. This bacterium has the ability to increase the production of its virulence factors during periods of stress. Four characteristics allow S. aureus to cause infection: adhesion/colonization, invasion, evasion and biofilm.

S. aureus is effective at adhering to and colonizing the skin, allowing it to eventually invade the bloodstream. The bacterium secretes a chemical called teichoic acid onto its surface, which allows it to bind to the skin. It then invades the host’s cells through disruption of the skin barrier by secreting exfoliative toxins, which form pores in skin cell membranes. This often happens during periods when the immune response is compromised or when there is a break in the skin.

The bacterium evades cellular immune response by using anti-opsonizing proteins, which prevent phagocytosis by host neutrophils. In addition, the bacteria secretes leukotoxins, which kill host leukocytes and express superantigens and toxic shock syndrome Toxin-1. This subverts the normal immune response by causing the immune system to kill its own T cells.
S. aureus is also effective because it has the ability to create slimy biofilms on damaged skin, fitted medical devices and heart valves. Biofilms provide protection against immune cells and may restrict the penetrations of some antibiotics.(3)

S. aureus has developed resistance to several antibiotics, including penicillin, cephalosporins, methicillin, vancomycin and inezolid. Infection typically occurs at the site of skin trauma, including minor trauma, appearing at first like an insect bite. Inflammation causes an increase in redness, swelling and pain. The trauma progresses to appear similar to a boil with drainage of pus.

Caregivers who suspect MRSA in a patient should cover the area with a clean bandage to prevent spread of infection and clean all equipment that has made contact with the patient’s skin.3 He should be sure to inform the receiving caregiver of his suspicions and to thoroughly wash his hands following transfer of care. MRSA is difficult to treat because of its antibiotic resistance. In a comparison between hospitalized patients who had methicillin-sensitive S. aureus and patients who had MRSA, MRSA was associated with a 50% greater likelihood of in-hospital death.(3)

ErysipelasErysipelas, also called superficial cutaneous cellulitis or St. Anthony’s fire, is a skin infection that can be caused by streptococcal species bacteria or by gram-negative organisms. Erysipelas enters through a disruption in the skin, affecting 2.49 per 1,000 patients per year.(4,5) Infestation targets the epidermis and dermis, and may include the superficial lymphatics.2 The majority of cases involve the lower extremities and face and look like a raised red rash. The provider may also note a lesion, blisters, fever and pain to the site.(5)

Those at highest risk of infection are infants, children, older adults and immune-compromised patients.(2) Other risk factors include disruption in the skin barrier, venous insufficiency, pedal edema, lymphedema and obesity.(2)

Treatment of erysipelas includes antibiotic therapy and pain management. Although infection is generally localized and treated with antibiotics such as penicillin, patients with erysipelis are at risk for bacterial spread into the bloodstream and potential septic shock.(5)

Impetigo
Impetigo is highly contagious and can be classified into two types: nonbullous and bullous. Infection is most commonly seen in children and immune-compromised populations and results from introduction of bacteria through breaks in the skin from trauma, burns, insect bites and preexisting skin diseases.(2)

Impetigo is spread in areas prone to warm weather, crowded spaces and poor hygiene.(6) On rare occasions, infection may progress to cause cellulitis, inflamed lymph nodes or streptococcal infection of the kidneys.

Bullous impetigo is a result of an S. aureus infection, characterized by its flaccid vesicular and bullous lesions, which release yellow fluid when ruptured.(2)

S. aureus bacteria locally excrete exofoliative toxin resulting in formation of blisters.(7) Bullous can be differentiated from nonbullous due to its light-brown crusted pattern and large diameter.(2) Nonbullous impetigo, which is more prevalent, is characterized by both fluid- and pus-filled sacks that can develop into “honey-crusted” sores or plaques.(2)

Due to impetigo’s contagious nature, it’s important to wear all-body substance isolation equipment during assessment. Isolation and decontamination of equipment that touches the lesions is imperative to prevent the spread to uninfected areas on the infected patient, to other patients and to the provider. If impetigo is suspected on a patient, a light wrap over the site with gauze will help to prevent contamination of equipment and other areas.

Impetigo doesn’t cause pain and will likely not be a result of an emergency call. Although generally superficial, if left untreated, infection can spread extensively.6 Management should focus on the underlying reasons for infection, including past skin trauma, burns, underlying skin conditions and immunosuppression secondary to AIDS or from immunosuppressant drugs following a transplant. Normal treatment is outpatient and includes topical antibiotics, such as Neosporin or oral antibiotics.(2,6)

Cellulitis
Cellulitis is local soft tissue inflammation resulting from bacterial infection caused by normal flora or by exposure to outside bacteria. In adults, staphylococci or streptococci are the most prevalent bacteria causing cellulitis, while Haemophilus influenza is prevalent in children.

Cellulitis typically results from a break in the skin, such as a scratch, abrasion, laceration or insect bite. Other risk factors include immunosuppression, diabetes, obesity, IV drug use and underlying skin conditions. Immunosuppressed patients may have systemic involvement characterized by fever.(6)

Once infected, skin cells, and immune cells on the skin and mucosa, release cytokines that increase infiltration of the immune cells lymphocytes and macrophages in the area of infection. These cells rapidly destroy the invading bacteria, usually resulting in clearance of the bacteria within 12 hours after infection.(6) This rapid response doesn’t allow enough time for the lymphatic fluid to drain into the lymph capillary; localized inflammation, erythema, warmth and tenderness result. Though uncommon, if a more serious infection occurs, the patient may present with enlarged lymph nodes.(6)

Cellulitis may mask an abscess. Suspect a co-occurring underlying skin abscess if the patient has a large amount of swelling to one particular site, pain on movement of the affected area and poor effectiveness of antibiotic treatment.(2)

Scabies
Scabies is a highly contagious skin infection caused by a microscopic mite called Sacroptes scabiei var Hominis. Infection is most prevalent in crowded spaces and in areas where hygiene may be poor, such as long-term care facilities, acute care hospitals, developing countries, childcare facilities and overcrowded urban areas. Women and children are more often affected than men.(8)

Scabies is characterized by severe inflammation of the skin, grayish or skin-colored curvy lines on the epidermis close to 5 mm in length, a rash appearing similar to pimples and itchiness. Norwegian scabies, a more extensive type of scabies, is characterized by raised crusts on the skin and may include both rash and itchiness.

Infection is typically caused by direct contact of skin of an infected person; however, mites can survive at room temperature for 24–36 hours without a host. In primary scabies infestation, clinical signs will present four to six weeks after exposure. In those with previous infestation, signs will present 24–48 hours after exposure. Scabies tend to be localized to the webbing of fingers, wrists, elbows, axillae, the abdomen, inguinal folds, male and female genitalia, under the breasts of women and gluteal folds. Immunocompromised patients—such as infants, the elderly, malnourished, Down syndrome and cancer patients—are at especially high risk.(9)

Scabies infection occurs when a male and female mite mate on the skin’s surface. The female mite burrows into the epidermis, where she will lay only two to three eggs within a two-month period, incubating for three to four days each. Although very few of these nymphs survive to become adult mites, those who reach adulthood will burrow upward onto the skin’s surface, where they will mate, burrow and continue infection.

Symptoms are caused mainly by the burrowing of the mites, but allergic reactions are known to occur in response to eggs, saliva and feces deposited under the surface of the skin. Although generally local, patients infested with scabies are at increased risk of fissure development and mortality secondary to bacterial infection during infestation. Scabies may also have long-term consequences; studies have shown increased risk of end-stage renal disease in adults who experienced infestation as children.(9)

Treatment of scabies infection involves use of a skin cream, generally permethrin, over the entire body. All members of the patient’s household and all sexual partners should also be treated, and clothing should be washed in hot water and carpets cleaned. Though infection is generally easily treated, occasionally infection may involve oral medications. Caregivers who suspect scabies should use body substance isolation as directed, thoroughly clean all equipment and wash clothing in hot water.(9)

Necrotizing FasciitisNecrotizing fasciitis is an umbrella term used for emergent states of bacterial infections involving skin necrosis, vascular thrombosis, inflammation and possibly muscle and fat. The primary bacteria involved are S. aureus, streptococcus, e coli, various aerobic and anaerobic infections and water-borne organisms.(2) Though first recorded by Hippocrates in the 15th century BC, mortality remains as high as 73% when left untreated.(10)

Risk factors for necrotizing fasciitis infection are substance abuse, diabetes, recent surgery or trauma, vascular problems, renal insufficiency, immunosuppression, varicella, perineal infections, malignancies and malnutrition.(2) Advanced age contributes to increased risk of infection and a much greater risk of mortality.(10) Although studies remain inconclusive, some research has suggested that the use of non-steroidal anti-inflammatory drugs may predispose the patient to infection and may mask symptoms, delaying diagnosis.(11)

Initial presentation includes erythema, edema and warmth to the affected site. Infection usually occurs on an extremity and will have no distinct borders. Fever and hypotension may be noted in this early stage. These symptoms quickly progress to include crepitus to the site, bullous lesions, disproportionate pain to the site and restricted limb movement secondary to pain.

The patient will experience vomiting, fatigue and nerve involvement. Visible skin necrosis is a late sign, and differentiation between necrotizing and non-necrotizing fasciitis is generally made in the operating room. A provider who finds suggestive symptoms should maintain an appropriate index of suspicion. Necrotizing fasciitis generally involves fat and fascia with varying levels of skin involvement, leading to much more extensive damage than is visible to the provider.(2)

A particular type of necrotizing fasciitis of note is Fournier’s gangrene, which generally occurs on the skin and fat of the perineum, leading to a large infected site that normally doesn’t include the testes. Fournier’s gangrene usually affects men older than 50 and is strongly associated with urinary, genital, anal and abdominal infections.(2)

Incidence of necrotizing fasciitis is low, at 0.4 adults per 100,000, and at an even lower rate for pediatric patients.10 Some types of infection are relatively mild and respond well to treatment. Complications leading to limb loss and death are highest when toxins are involved.(12)

Treatment involves debridement, hemodynamic support, surgery including potential amputation and skin grafting.10 Nutritional supplementation and hyperbaric oxygen treatments have been shows in some studies to be beneficial.(10) Prehospital care of suspected necrotizing fasciitis involves hemodynamic support and covering the affected area with sterile gauze.

Conclusion
You receive a call from your supervisor just as you finish dropping a patient off at the emergency department. Your supervisor says that an 80-year-old female patient you cared for a month prior was just re-admitted to the hospital for a rash that turned out to be scabies. You’re pulled from your shift and sent to the clinic, where you are found to have scabies infestation and are given a topical cream, which makes you noncontagious in a matter of hours. You wash all of your clothing in hot water and are allowed to return to work the next day, though your wrists remain itchy for weeks.

Skin infections occur for a variety of reasons, including bacterial infection and arachnid infestation. Although skin infections are often no more than a nuisance, if they’re left untreated, some can lead to systemic infection that may lead to sepsis and death. Appropriate body substance isolation should be used at all times, and all equipment used on patients should be cleaned after each patient contact to prevent the spread of skin infections.

Cynthia Goss, BA, MICP, is a paramedic in Palm Springs, Calif., and a frequent contributor to JEMS.James F. Goss, MHA, MICP, is regional manager for NCTI in Riverside, Calif., and a frequent contributor to JEMS. Contact him at james.goss@emsc.net.Joslyn De Los Santos, EMT-B, is a student in the emergency medical care program at Loma Linda University.Dave Williams, MICP, is a student in the emergency medical care program at Loma Linda University.Ann Fang, EMT-B, is a student in the emergency medical care program at Loma Linda University.
Randy Yergenson, MICP, graduated from the emergency medical care program at Loma Linda University.

2. Systemic infection of cellulitis is characterized by __________.
a. Redness and warmth to the site
b. Double vision
c. Fever
d. Pain and swelling to the site
3. All of the following are at increased risk for a skin infection except:
a. Immunosuppressed
b. Patients with venous insufficiency
c. Adolescents
d. IV drug users

4. Fournier’s gangrene is _________.
a. A type of necrotizing fasciitis affecting the perineum
b. The smell associated with tissue breakdown
c. Associated with carbuncles
d. Progressive infection originating in the digits and moving inward to the torso

5. What is the length of time between exposure to scabies and expression of symptoms in the previously unexposed?
a. Two to three weeks
b. Symptoms are only expressed only later in life when the patient becomes immunosuppressed
c. Twenty-four to 48 hours
d. Four to six weeks

6. Following all calls involving a suspected skin infection, the provider should do all except:
a. Thoroughly wash his hands
b. Clean all equipment that made contact with the patient
c. Inform the receiving caregiver of the potential skin infection
d. File exposure paperwork

8. Impetigo will most often present as _________.
a. Painless crusted blisters with history of a break in the skin
b. Redness and swelling following exposure to tetanus
c. Painful crusted blisters with a history of bone infection
d. Raised red rash with a defined border with history of obesity